Back in August, I was invited to speak at Annapolis Lodge No. 89 in Maryland. Among the brethren I met that evening was Brother Eric Madison. He and Brad Finnsson have formed FraternalSoft Inc. and created the great iPhone software application, Masonic Traveler. Masonic Traveler is an outstanding lodge finder ap that works intuitively with your iPhone, providing names, address, contact information, maps and step-by-step directions, and more for almost every Craft lodge in the US. I can't recommend this application heartily enough. It has helped me several times already, and well worth its $7.99 price.
Obviously, its biggest shortcoming is that it is only as accurate as the information given to FraternalSoft by grand lodges, or found by them on lodge websites. Thoughtfully, they have included a feature request and contact support function within the ap, so you can help them stay up to date. The more popular it becomes with Freemasons, the more accurate its database will be.
While you're at it, check out iCraft - Interactive Tools of Freemason for the iPhone. The 99¢ ap features a functioning plumb, level, and noise-making gavel, along with a square, trowel and 24-inch gauge.